Prices clawed up from previous three-week lows in thin dealings, but market participants seemed reluctant to add to positions in the early going.
"We are all waiting for one important event at 2:15 today. I think the majority of markets are going to be quiet in anticipation of what happens," said Graham Leighton, vice president of precious and base metals at Societe Generale, referring to the Fed announcement.
"A 25 basis point increase has been fully discounted into the market - the question is what statement is he going to make and that's what we're all waiting for," he added.
"We don't expect much of a change" from the Fed's measured approach to tightening, said Leighton.
Markets widely expect to see a quarter-point rate increase to 2.5 percent at about 2:15 pm.
Technically, gold is caught in a trading range from about $420 to $430, analysts and traders said, awaiting further direction from currencies.
Spot gold was firm at $421.60/2.40 an ounce, which was not far above Tuesday's New York close at $420.80/1.60. The afternoon fix in London was down at touch at $421.60.
COMEX March silver rose 6.5 cents to $6.795 an ounce, dealing from $6.72 to $6.82. Spot fetched $6.76/79 an ounce versus $6.70/73 at yesterday's New York close. The fix was at $6.73.
NYMEX April platinum extended its retreat from the $880 level to trade at $874 an ounce, down $4.90. Spot platinum stood at $869/873.
March palladium slipped $1.40 to $190 an ounce. Spot fetched $184/189.